Intervention: BIIB092 or placebo control will be administered as an intravenous infusion

Phase: Phase 1

Duration of Participation: Approximately 30 weeks, including 6 weeks of screening, 12 weeks of dosing, and 12 weeks of follow-up safety visits

Purpose of the Study

The primary purpose of this study is to see how safe and well tolerated the study drug BIIB092 is at different drug amounts and to measure the amount of study drug in subject’s blood and cerebrospinal fluid (CSF) after taking the drug.

Eligibility

Inclusion Criteria: Subjects must be between 41–86 years of age and be able to walk five steps with minimal assistance (stabilization of one arm or use of cane/walker). Subjects must also have a Mini Mental State Examination (MMSE) score ≥20 at the screening visit, be willing and able to have three brain MRIs and three lumbar punctures performed, have a reliable caregiver who has at least three hours of contact per week and is willing to accompany the subject to study visits, and have stable medications for parkinsonism for at least three months prior to screening.

Exclusion Criteria: Subjects must not have other significant neurological or psychiatric disorders including (but not limited to) Alzheimer’s disease, dementia with Lewy bodies, prion disease, Parkinson’s disease (which has not subsequently been revised to PSP), any psychotic disorder, severe bipolar or unipolar depression; must not be currently on any other investigational immunomodulator or monoclonal antibody; or have history of clinically significant hematological, endocrine, cardiovascular, renal, hepatic, gastrointestinal or neurological disease.

Follow-up: Additional single follow-up visit after the end of the study of the placebo-controlled phase

Materials Needed Before Evaluation: Participants meet criteria for probable or possible PSP (based on the National Institute of Neurological Disorders and Stroke & Society for Progressive Supranuclear Palsy).

Costs: No costs will be charged for any of the study procedures. Parking will be validated at UCSF public garages for all study visits, and subjects will be reimbursed $75 for each scheduled visit and $75 for additional MRI scanning and/or lumbar puncture visits to help defray incidental expenses incurred in the course of participating in this study. Reimbursement is available for travel and accommodations that are necessary for participation in the study.